Browsing by Author "Oliveira, R."
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- Ceruloplasmin expression by human peripheral blood lymphocytes: a new link between immunity and iron metabolismPublication . Banha, J.; Marques, L.; Oliveira, R.; Martins, M. de F.; Paixão, E.; Pereira, D.; Malhó, R.; Penque, D.; Costa, L.Ceruloplasmin (CP) is a multicopper oxidase involved in the acute phase reaction to stress. Although the physiological role of CP is uncertain, its role in iron (Fe) homeostasis and protection against free radical-initiated cell injury has been widely documented. Previous studies showed the existence of two molecular isoforms of CP: secreted CP (sCP) and a membrane glycosylphosphatidylinositol (GPI)-anchored form of CP (GPI-CP). sCP is produced mainly by the liver and is abundant in human serum whereas GPI-CP is expressed in mammalian astrocytes, rat leptomeningeal cells, and Sertolli cells. Herein, we show using RT-PCR that human peripheral blood lymphocytes (huPBL) constitutively express the transcripts for both CP molecular isoforms previously reported. Also, expression of CP in huPBL is demonstrated by immunofluorescence with confocal microscopy and flow cytometry analysis using cells isolated from healthy blood donors with normal Fe status. Importantly, the results obtained show that natural killer cells have a significantly higher CP expression compared to all other major lymphocyte subsets. In this context, the involvement of lymphocyte-derived CP on host defense processes via its anti/prooxidant properties is proposed, giving further support for a close functional interaction between the immune system and the Fe metabolism.
- Crosstalk between inflammation, iron metabolism and endothelial function in Behçet’s diseasePublication . Oliveira, R.; Napoleão, P.; Banha, J.; Paixão, E.; Bettencourt, A.; M da Silva, B.; Pereira, D.; Barcelos, F.; Teixeira, A.; Vaz Patto, J.; Viegas-Crespo, A.M.; Costa, L.Behçet's disease (BD) is a rare chronic vasculitis of unclear etiology. It has been suggested that inflammatory response has an important role in BD pathophysiology. Herein, we aimed to study the interplay between inflammation, iron metabolism and endothelial function in BD and search for its putative association with disease activity. Twenty five patients clinically diagnosed with BD were selected and twenty four healthy age-sex matched individuals participated as controls. Results showed an increase of total number of circulating white blood cells and neutrophils, serum transferrin, total iron binding capacity, mieloperoxidase (MPO), ceruloplasmin (Cp), C reactive protein, β2 microglobulin and Cp surface expression in peripheral blood monocytes in BD patients comparatively to healthy individuals (p < 0,05). Of notice, the alterations observed were associated to disease activity status. No significant differences between the two groups were found in serum nitric oxide concentration. The results obtained suggest an important contribution from innate immunity in the pathogenesis of this disease. In particular, surface expression of leukocyte-derived Cp may constitute a new and relevant biomarker to understand BD etiology.
- Helicobacter pylori prevalence, histological and antibiotic resistance patterns among paediatric patients, at a single hospital in Lisbon, during a 5- year periodPublication . Santos, A.; Pereira, L.; Paixão, P.; Braga, A.C.; Oliveira, R.; Catarino, A.; Oleastro, M.Background : Decreasing prevalence of H. pylori infection has been reported worldwide, in parallel with the improvement in sociodemographic conditions. In contrast, in Portugal, there is still a high prevalence of infection, including in pediatric population, and of gastric carcinoma. Aim : This study aims to evaluate H. pylori prevalence, histological and antibiotic resistance patterns in symptomatic Portuguese children/adolescents attending a hospital in Lisbon.
- Lymphocyte ceruloplasmin and Behçet's diseasePublication . Oliveira, R.; Banha, J.; Martins, F.; Paixão, E.; Pereira, D.; Barcelos, F.; Teixeira, A.; Patto, J.V.; Costa, L.Behçet's disease (BD) is a rare chronic inflammatory disorder of unknown aetiology. However, it has been postulated that a dysregulation of the prooxidant/antioxidant balance may be important to its pathogenesis. Ceruloplasmin (CP) is an acute phase protein expressed at the surface of peripheral blood lymphocytes (PBL) with antioxidant properties and with a relevant role in iron (Fe) metabolism.